Wrench



(No Model.)

S. ROBINSON.

WRENGH.

No. 299,l65. Patnted May 27, 1884.

tmiren %marre Parent* written,

SQUIRE ROBINSON, OF SOUTHINGTON, CON N ECTICUT.

WRENCH.

fziPI-CIPICATION forming part of Letters Patent No. 299,l65, dated May 27, 1884.

Application filed December 29, 1883. (No model.)

To all whom it may concern: v

Be it known that I, S UIRE ROBINSON, a citizen of the United States, residing at Southington, Hartford county, Connccticut, have invented a certain new and useful Improvement in Wrenches, of which the following is a specification.

This invention relates to that class of monkey-wrenches which has an adjusting-screw separate from the wrench-bar; and it consists of an integral feri-ule, step, and shoulder constructed in a particular way and forming one piece of such a wrench; and its object is to obviate certain evils which have heretofore characterized such wrenches. All such wrenches have an adjusting-screw parallel with the wrench-bar, and furnished with a milled head, commonly called the rosette, and with a trunnion, upon which it revolvesin a bearing made in astep which projects from the wrenchbar. To secure ease and accuracy of adjustment, it is necessary that the adjusting-screw shall have but little longitudinal motion. The step prevents backward motion of this kind; and to prevent forward motion of this kind a 4 shoulder has always been made to project from i the wrench-bar in front of the rosette; but

never, to my knowledge, have that step and shoulder been made of one piece, and in such a way as to admit of the insertion therein of an integral screw and rosette, It was always desirable to make them thus. If made in separate pieces, the great backward thrust, which is incident to the adjusting-screw of all such wrenches, tends to force the step backward from the shoulder, and, as soon as the parts of the wrench become worn, does, in fact, so force the step. This increases the distance between the step and the shoulder, and thus increases the longitudinal play of the adjusting-screw, and thus increases the time and manipulation necessary to adjust the wrench to different sizes of nuts, and by increasing the liability that this adj ustment will not be accurately made, increases the danger of wearing or breaking off the corners of the nuts and of ultimately breaking the wrench.

To obviate the evil explained in the last paragraph, prior inventors have made a shoulder project from the wrench-bar on the back side of the rosette, corresponding with that on its front side, the two shoulders constituting the opposite walls of a notch cut into the wrench-bar. The object of such a rear shoulder was to take the backward thrust of the adj Listing-screw, thus rclieving the step from that thrust; but this plan introduced a new evil. It deprived the adj usting-screw of the support it fornerly had in the direction of its axis, and gave it a support only on one border of its milled head. Thus the strain became a diagonal one, much to the injury of the parts sustaining it. Another prior inventor has endeavored to obviate the evil by means of an integral step, ferrule, and shoulder or supporting-arm; but, in order to insert thescrew into his device, it was necessary to make it separate from the rosette, and to piu the two together after the trunnion of the screw was passed through the aXial bore in the rosette into the trunnion-bearing. That Construction is objectionable because it throws the great backward thrust of the screw either upon the pin which holds the rosette to the screw or upon the end of the trunnion. If thrown upon the pin, the strain soon breaks it, and if thrown upon the end of the trunnion, the friction soon wears the trunnion-bearing deeper, and thus ultimately throws the strain upon the pin with much the same result as before. My invention remedies the evil under contemplation without introducing any evil or difficulty in its place.

Figure 1 of the accompanying drawings is a side elevation of a wrench with my invention, indicated by the letters c, (Z, and e, and forming a part of the wrench. Fig. 2 is a central longitudinal section of the main feature of my invention, with the integral headed adjusting-screw inserted therein. Fig. 3 is :a similar section with the screw being inserted therein.

The parts A, B, C, D, E, and F are all old, and are so familiar that they require no description here. The trunnion Gi s made shorter than usual, being only about one-eighth of an inch long in wrenches of the size illustrated.

H is the integral ferrule, step, and shoulder, which constitutes the main feature of my invention, I being the ferrule, J being the step, and K being the shoulder of the same. The ferrule is cylindrical as to its right-hand part,

IOO

.and the shoulder K projects upward from the left-hand ends of the same edges of those walls. The shoulder K thus forms a bridge, uniting 'the left-hand ends of those walls, and the step J forms a bridge, uniting their right-hand ends, and integral also with the cylindrical part of the ferrule. The upper surface of the shoulder K is concave longitudinally of the wrench, but it is not essential that the concave surface should be high enough to furnish permanent support to the screw, nor indeed that it should have any concavity at all or any projections reaching around any part of the circumference of the screw. The forward face, O, of step J is provided with the bearing L for the trunnion G. Instead of being flat, as that 'face of such a step has heretofore been made, this step has a shallow concave groove, M, extending downward from the trunnion-bearing L, and it also hasashallow concave groove, N, extending upward from that hearing, but growing constantly shallower till its bottom reaches the plane of the face of the step, just before it reaches the upper border of that face O. The flat portions of the face just mentioncd and the opposite face of the shoulder K are parallel, and are just far enough apart to admit the thickness of the rosette between them, and to allow the rosette a longitudinal play of about onefortieth part of an inch.

The mode of assembling this wrench is as follows: The integral part H is taken'in one hand and the rosette-headed scre'w in the other, and both are placed in the relative positions shown in Fig. 3. Then the left-hand end of the screw is raised and the trunnion G slips into the hearing L through the concave groove N. In that movement the end of the trunnion describes an arc of a circle, of which the outer edge of the botton of the concave surface of the shoulder K is the center, and that arc terminates some distance within the trunnion-bearing L, when it reaches the lower surface of the same. Thus when the two integral pieces are in the positions shown in Fig. 2, the trunnion-bearing furnishes a support for the lower side ofthe trunnion. It also furnishes a support for its upper side as against any movement parallel with the face O of the step J, and no other movement in that general direction is possible after all the parts of the wrench are assembled. The trunnion -bearing L also furnishes a support as against any sidewise movement of the trunnion, because the face O of the step J has little or no concavity at the sides of the bearing L. The two parts being thus assembled, and

the part C being slipped upon the part B, the

part His also slipped upon the part B, and the part D is screwed into the part C. Then the handle F is slipped upon the shank of the part B and fastened thereto with a nut in the usual manner.

The mode of operation of this wrench, when thus completed, is the same as that of other wrenches of its class; butbecausethe stepJ and shoulder K are integral, while the screw and rosette are also integral, the utility and durability of the implement are both increased for the reasons hereinbefore explained.-

It is not essential to this invention that the left-hand portion of the piece H should have flat walls. -Nor need the piece H be made of one piece of metal, for it may be made of several pieces if they are incorporated into one, by means which make the whole substantially integral in point of strength. Neither is it essential that the piece H should have the right-hand cylindrical part. That part maybe omitted or may be made separate from the residue. If made separate, it may have an interior screw-thread taking into a screwthread in the shank of the bar B, and thus intercepting the backward strain which otherwise would pass from the piece H to the wooden handle F and possibly split thelatter. That device for intercepting that strain is old, and I disclaim it.

I claim as my invention- The integral piece H, constructed with the concave grooves M and N on the face O of the step J, and constructed otherwise substantially as described.

SQUIRE ROBINSON.

Witnesses:

CHARLES D. BARNES, EDwIN G. LEWIS. 

